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00:04 Hello, it's Scott Manley here. A few weeks ago, I was at open source with a whole bunch of other creators. And immediately afterwards, NASA as research facility put on a tour for a bunch of cool people who were interested in space flight. And so, as part of this, I got to shoot some video in a bunch of cool places behind the scene. And so I want to bring you behind the scenes at NASA's thermal protection materials lab.
00:29 >> What's your name? >> Matthew. And I'm smarter every day, by the way. So yeah. Yeah, >> it's a serious lab code, man. >> Scott, man. >> Scott, man. >> Hello. >> Hello. >> So welcome. Uh we are going to tour the um sensors and TPS advanced research labs. Uh we are part of the thermal protection materials branch here at NASA as um the lab that we're going to walk through is the merging of two labs.
00:50 One used to be the sensor lab, one was the thermal protection materials that we emerged and so now we're star labs. The work that we do here, we do research and development. So uh for example the first stop here that's where the space shuttle to tile material was invented is do R&D to invent and develop materials uh increase their technology readiness levels so that they are ready for mainstream use and then we technology transfer to companies like um Canopy Strat Launch um uh SpaceX Blue Origin.
01:22 So when when they need a thermal protection material, they come to us uh we we get a space act agreement together, they pay us and then we teach them how to make those materials. >> So the majority of US spacecraft that have been flown with heat shields have used material that was developed by NASA as they have the labs to develop the hardware and they have facilities like the arcjet so that they can actually test this under re-entry conditions.
01:43 And so this includes both ablative heat shield material that gets consumed over time and passive material which can be refflown multiple times. And we began this tour in the lab where they figured out how to make the low density low conductivity tiles that made the space shuttle possible. So within this space, I often say that we should have a bronze bronze plaque because these fiber bins right here, the downdraft table, the Vblender off in the corner, and the casting tower, these are the original equipment that was
02:15 used to invent the shuttle tiles. And then they were technology transferred out to Lockheed, and they did the mass production for shuttle. And then nowadays, I think Loheed is also making the back shell tiles for Orion. Um, but these tiles start off with, um, silica fiber, uh, Q fiber, quartz felt, also some of the names it goes by. And I have these bags so I can pass them around and you can feel what the the different fibers look like.
02:39 But it's a mixture of aluminum oxide fiber, silica fiber, the fiber called aluminum silicate, and a little bit of silicon carbide powder for emittance so that it's not pure white. So these all get mixed up with some deionized water. They go in the VB blender and you end up with this sort of runny wet oatmeal looking material. That mixture then goes into the casting tower that's right here with the acrylic clear front face on it.
03:03 And the water gets drawn off the bottom till it's uh what we call a wet cake. And once we get the water drawn off and we know the cake height, we can calculate the the final pressing height to get the density that we we desire. So then it gets pressed to that height. the rest of the water gets drawn off and what we have right here is the result of that process.
03:24 Um, so this this is a dried cake that is now going to go for firing. When it's fired and trimmed, this is what it looks like. Um, all of the equipment here, you can see all the duct work over your head. That all goes to a very large industrial dust collector outside that collects the dust so we don't have to wear bunny suits and respirators when we work with it.
03:44 Um, so everything is everything is dry. No lubricants, no oils anywhere. um all gloved hand. >> I have scripts to write, videos to edit, and the occasional actual airplane to fly when the weather and the schedule line up. Somewhere in all of that, looking after my own health keeps sliding down the priority list. The old process made it worse. You'd end up in research mode, 20 tabs open, trying to work out who's in network, calling offices that put you on hold, and then forget about you.
04:12 That little bit of phone anxiety for me is enough to make me close the laptop and decide that it can wait again and again. And that's why I'm happy to say today's video is sponsored by ZokDoc. Zodoc is a free website that lets you search and compare local doctors who will take your insurance. They have over 150,000 providers across over 200 specialties in all 50 states.
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05:22 So, so this this shell rotates and hydraulically mixes the slurry. And as it goes back and forth in that hydraulic mixing, it passes by that intensifier bar that's rotating at about 4,000 RPM. and that chops the fiber. So, >> the amount of chop that you're you're you're going to um apply to the fibers determines the fiber length. And different fiber lengths, there's a really narrow window to where you can achieve something as low as an 8 pound density tile or scrap.
05:51 Uh when you go for 17 to 20 pound per cubic foot densities, uh it's it's much easier to get because you're you're pressing them to a a higher pressing depth. But on the lower press for a lighter press for a say eight and 12 pound densities, they're they're more challenging to make. So the fibers start off what you had in the bags over there, we take um a certain amount of those uh with deionized water, silicon carbide powder, and it goes in the the VB blender here.
06:19 And then this is what it looks like after it's been run for about 17 minutes. >> If you ran it longer, it get shorter, >> right? It gets shorter and shorter. And the shorter the fibers, the more likely you're only going to make a 20 pound density tile or even greater. And the higher the density, the less effective it is as a TPS. Uh you have a weaker strength through the thickness, stronger through the sides.
06:38 And its ability to transfer uh temperature from outer to inner mold line is very limited because the fiber direction is horizontal and it's about 94% air. So air is not a good conductor. the heat hits those fibers and it it radiates out horizontally with the outer surface and it will maintain the majority of its heat uh just at the outer surface. So you could have with a one of these tiles with a what we call an emittance coating, you could have 2400 degree outer temperature and 2 in away it's maybe 100 degrees.
07:09 Over the time we've been doing it hasn't changed at all. >> They they are right. They are they are static. It's it's that effective. And even um some of our space partners right now, I won't name names came to us and they wanted something that was better and we told them this is still state-of-the-art for reusable. they went off to try to make their own and they came back a few years later and said we need to do a tech transfer because we need to know how to make what you're making.
07:34 So it it is still state-of-the-art where there couple of different recipe families. There's AEB which is the one here. There's F FRCI which is fiber reinforced composite. It has a different mix of the fibers and then there's the locked alli industry ones which are pure silica with silicon carbide. But those are pretty much three the three families. And within those densities from 8 pound per cubic foot to about 20 pound per cubic foot.
07:58 If if you look at this, this would be the top surface that has the 12 on it. You don't really see a fiber direction. But if you look at the side, you can see the fiber layers horizontal. >> And so is was it compressed in this direction? >> It was compressed in this direction. So when the when the fiber goes in this casting tower, the and the water is drawn off the bottom.
08:16 The fibers will settle on the bottom and they will lay horizontally. uh if you draw it off at the right rate, if you try to go too fast, uh you don't get the right fiber lay. And so here's here's a bucket if you wanted to give it give it a stir to see what the the large mix looks like. Um it's >> really high tech. >> It is it is super high-tech. I mean, >> this is really what I expected.
08:38 [laughter] >> Uh that one we can't talk. >> Okay, just I was I'm wondering >> I can put a glove on and I can I can rub a little up the corner if you want to see how this in its current state it is unfired. So it's very fryable. Okay. So, this is the what comes out of that, >> right? That's that's a green billet has not been fired. When it gets fired and cut and cleaned up, that's what it looks like.
08:56 >> That's what Yeah. >> And then this will be further cut to the particular tile shape before. >> Yeah. >> And so, the room that we're in here that we call this our roughing room. So, anything that's going to be cut from this gets cut into its rough stock and then it's going to go to our machine room, which will be uh in a little while. >> Yeah. These these would be reusable materials for multiple reuses as a thermal protection system, but they're not quite ready yet.
09:18 They are still slightly off-white. So, you can see sort of the grayish appearance of the slurry that's in the beaker right here. That's because of the silicon carbide powder that's that's part of the mix. So, when when you're out um on orbit, white is reflective, so it's a good insulator for solar energy. But when you're re-entering, white is not good because it's going to melt.
09:38 So, you need something that's that's good for the convective energy from re-entry. And I'll show I'll show you what that is in a little bit. So, if you try to re-enter with this bear tile, uh you'll you'll get um a little bit of the way into your re-entry and then temperatures are going to increase and then it's just going to melt and the glass is going to flow like water.
10:01 >> For like uh Orion, it's reverse. The black uh TPS is on the back shell now. And you've got the you know the ablative on the >> So we do have um an ablater here. This since you mentioned it, we got so sidetracked on this I didn't I overlooked. This is a block of flight a coat for Artemis. Um probably about half of a median family home in the Silicon Valley value.
10:22 This is a piece of block a coat that's a just a cut off trimmed scrap. So you I can pass this around. You can handle this. So this is the ablater. Um we don't make the abladers here typically at least for AFC coat that's made by Lockheed for and also formerly by Textron. >> Is that the new formulation that's more um porous? >> I am not sure which one you're holding right there.
10:46 >> Okay. >> Uh this one is the panel. >> Okay. >> So one of my favorite things I saw open source were these heat shield samples from Artemis one and Artemis 2 on the bottom showing the difference between the different re-entry plans. And they were able to extract these thanks to Bart and Lisa. >> This is a tool. After Artemis one came back and there were a lot of anomalies in the heat shield, we needed to secure as much of that heat shield for analysis as possible and no tools existed to do that.
11:15 So, um, this is my brainchild. This is BART. Uh, this is the block a coat removal tool. >> The what? >> It's right here. The block a coat removal tool. So, [clears throat] we we have Bart here. Uh this is a BART that's partially set up just for um uh in-house testing and for training for disassembly. Uh kind of the RNR that we do in between uses. And this was used on Artemis one.
11:38 And each of these numbers that's written on here is the block number, the sample number that was extracted with this particular saw. So this is Bart and action. You made it. The these are by size. So Bart was the first for 8x4. Lisa was 5x6. And there were some little channel coupons and so I had a Maggie all ready to go. So >> in the next room was a furnace and it was time for the famous hot potato demonstration.
12:05 >> the thermal camera. >> Oh, that's a dramatic intro. >> Oh, there's the thumbnail. >> If you come closer, it's also nice in the winter time. >> Yeah. >> Yeah. Yeah. Okay. So, you can see that is still glowing inside. And so, we can pick that up. >> That's 2,000°. It's a little bit warm, so you have to kind of dance it back and forth a little bit, but you get a good roughly 30 seconds out of that where you can still see it glowing.
12:46 So, the reason why you can pick up these heat shield towels straight out of the oven is because they are so low thermal conductivity. As soon as they come out the oven, the outer layers cool just enough that you can touch them, but then the heat from the inside doesn't flow out quickly enough to burn your skin. And of course, you can still see it red hot.
13:05 That's because it's getting rid of heat via black body radiation. And that's the reason why you end up swapping the block from one hand to the other because of the heat radiating out of this rather than the heat conducting through your fingers because there's basically no thermal conductivity. Now, many of us already knew this and we also knew that there was a second tile in the furnace and so the inevitable question was could one of us try it?
13:32 >> I can't have I can't have non-NASA personnel. >> Oh, okay. Perfect. What if that person's wearing a Nomx suit? >> [laughter] >> Um, if you're wearing a Nomx suit or even all you're you're probably okay. [laughter] >> That was my point. >> Try to grab it up high so it stays as hot as possible. >> You tell me when >> you can see. How about I I'll hand it to you.
13:58 >> Yeah. >> Touch the cube. >> Yep. Right by the corners. >> Well, that's wild. Oh, yep. Your fingers get hot. Can you stand next to me? >> Yes. >> Yeah. >> There we go. >> Do you just do this for fun sometimes? >> Uh, no. I would in the winter time cuz it feels nice and [laughter] and warm. >> It's pretty slick. And you're saying the inside is still like 2,000°.
14:24 >> Yes. If you could cut that, the center of it is still 2,000°. >> Wow. Get a really close one. Let's do it. That's thumbnail right there. How's that? You see it? Yep. That's getting hot, [laughter] >> right? You can't you can't really see it glowing orange anymore, but you can feel the heat for sure. >> Oh, you can Well, I can feel the heat radiating onto my hand.
14:43 >> Like the my parts that aren't touching it like here. >> That's really >> Absolutely. >> Yeah. >> So, after the raw material has been manufactured, fired, and cut to the right shape, they need to apply special coatings. >> Yeah. [laughter] That that'll be the worst ice cream sandwich you've ever taken a bite out of. So, this is the coatings lab. So, we have I have two examples.
15:06 So trying trying to keep things sort of in line with Artemis. Um what we have is the RCG coating which is a coating because it sits on top of the tile. It does not penetrate. And then we have the toughy surface treatment which penetrates. >> Um I'm not sure if there's act if there's um toughy on the the back shell of Orion. Is there? Okay. >> Confirm there is.
15:28 >> Okay. Yeah. So, uh, normally the the place where this would have been probably used first on a vehicle is, uh, in the engine bay of the orbiter when it would launch and the the concrete would fall off, come back and hit the vehicle. Uh, this this protects it. So, I I'll pass this around in a moment. You can you can touch it. So, the um the process is kind of similar for these two.
15:44 They start off with what's called a borocyic glass powder. So, it's just a a white really fine glass powder passes around. You can kind of rot just kind of rub between your fingers. You can feel the granular nature of it. And just imagine as you're as you're rolling that the particle size that you're feeling is massive for what we want to do. We need to get this down um uh much much farther below two microns.
16:10 And so we what we do is we take the glass powder. Um this is tetraoronicide. There's a small amount in here because last time it was made it was $16,000 a kilogram. And by by today's pricing it's probably going to be at least double that. So, so RCG is going to be boricily glass powder SIB4. They get mixed in the ball mill right here, which is a aluminum oxide jar with aluminum oxide media.
16:36 It tumbles and then the impact energy from the media, uh, it reduces the particle size on on the RCG a little bit, but mostly what it's doing is it's mixing it. On Tffy, we actually have to get it down to that that sub4 micron. So, we mix those powders in the the ball jar. And if we're using the the ball jar ball mill process, it takes about a week and a half of running 24/7 to get the particle size where we want it.
17:03 Well, there's this other device that's called an attr. And what it uses is these um five mm zirconium oxide spheres. They get poured into this grinding tank and they get stirred by this agitator assembly. And so there's a lot more energy and a lot more impacts because of the smaller spheres. And so we can do with the atritter in about 90 minutes uh what it takes a week and a half to do in the ball jar.
17:28 And we get a more pure coating. So you see the weights on the the jar for the weight of the jar, the media, and the lid. That's the starting weight. When we're finished, we weigh them again to find out how much aluminum oxide was added to the coating because it's uh it's it's an undesirable addition to the coating. Not quite a contaminant, but it's undesirable.
17:44 It lowers the melting temp. and the attr. We get a little bit of the the tassel lining, but that sublimates when we fire the the coating and center it. And then what's left is a little bit of the for each each 90minute run, we expand about the volume of one sphere of the zirconium oxide. And that's much more beneficial to the coating than the aluminina is.
18:05 Um, so >> so the material is so fine it can penetrate in. Is that what I'm hearing? >> Right. So the the sub micro the the sub4 micron it allows the the coating to penetrate >> and it's just you paint that on. How do you apply that? >> You spray it. So that's what I was just going to say next. We have the spray booths that are behind you here and we use automotive type spray equipment and artist airbrushes.
18:26 Um and so the the pressure and the spray you don't spray it like a paint. You get the nozzle right up on the edge of the the the tile and so you're blowing the the alcohol and the coating. >> It just gets carried through the tiny porous >> Right. Yeah. And then we spray this in. We we don't want the the uniform density of the tffy. We want the majority since it it adds a lot of weight to the tile.
18:46 We want the majority out here where it can do the most good. So, it's it's sprayed in four applications typically. Uh and each one is a a smaller percentage of the previous so that [clears throat] you end up if you look at this when I pass it around, you can see that the depth is not terribly densified with Tffy, but that outer layer is is much more densified.
19:04 >> Yeah. So, it's basically making the entire matrix stronger. >> Yes. The matrix is stronger at the outer surface >> rather than just being painted on the outside which is the older material. >> Right? So this this is the RCG. The standard RCG is nice and jet gloss black like this. This is a modified RCG for something else, but it's a sample I have that is cut and gouged.
19:22 So you can see that it's about 12,000 of an inch thick once it's fired. And so it's um this this is the protection. So this this RCG coating is what keeps the heat right out here at the outer surface and then it radiates the heat back away because because of its emittance. >> So does it stops like the plasma actually flowing through it? Yeah. Yeah. >> Yeah.
19:43 So this also seals the outer surface of the tile as as as does tffy. It doesn't seal it against water. Um, as a matter of fact, first time I saw what they do for waterproofing, I was mortified because when we do test articles here and we do other things for for other flight projects, we're expected to have something that looks pristine like this. Well, when something like this is mounted on the shuttle, the first thing they do is take a syringe that's that's blunt and they pound it through that that coating and inject
20:08 waterproofing. So, this tile would have probably a a punch mark here and one here that have cracks that radiate from each of those punch marks. >> What >> exactly? If you ever make it to the air and space in in Virginia and you you're able to walk down the underside of the Discovery or you can see all these the places on the tile where they're there's a paint circle around them to identify where those those punches are and you'll see they're all over the acorage of the shuttle and that's where they their first
20:37 waterproofing is injected with a syringe. >> So did you have do would you have to reapply the water? Yes, waterproofing is reapplied. That's why they so during entry. Yes. That's why they are then marked so that they can locate the same hole and not have to punch multiples. >> But you can you can take this just please you can see three places where people have tested it with their thumbnail.
20:57 Ple please don't um alter these in any way or try to shed material off it. But you can feel it to see how light they are and Yeah. And so you can >> Oh, he's counted the thumbnail marks. He's going to know. >> Yeah, I know how many they are. And I I've seen all of your hands so I can [laughter] >> my fingerprints on this on the way out. where it aims.
21:14 >> Yeah, it is actually not it is not very it's not really adhered. Uh that coating when it's fired, it shrinks and so it is held onto the tile by the compression of Right. So So if if you if you tried to spray just the top surface, it will peel because it shrinks when it's when it's centered. It will peel off. So it has to wrap around the side of the tile at least about the what you have there is about a half inch or or a centimeter.
21:34 It has to wrap around at least that far or it will peel off. >> But yeah, this is I mean this is tougher, right? The acronym is a joke and the fact that it is tougher and stronger because it is um goes all the way through. >> Absolutely. It is humorous, but it it does work. >> Yeah. So, it it's interesting to see these particles must have been shoved in there by the pressure, I'm guessing.
21:54 And then it just creates a trace. >> Interesting. So, the >> So, they're they're they're they're pushed by the pressure from the the airbrush. They are also in alcohol. So, so this when it's sprayed, it's 25% solids in alcohol. And the rollers you see around the room, these have different coatings on them that are on the roller to stay in suspension.
22:13 If the power goes out or any of these things ever stop rolling, the powders settle in the bottom of the jar, the alcohol rises to the surface and you can never disperse this again to to make it usable. So if we have a power outage on the weekend and come in Monday, everything everything has to get thrown out and redone. >> So this is basically how it's stored.
22:34 It's not Yeah, >> they're right. They are not stored. These these are just here for historical samples and in case we ever need to take us something for analysis but but they they do not get stored like this because this is no longer useful for anything. >> So next up was the place where they were machining the tiles into shape and in this case they were primarily working with the avatlative material.
22:54 They were building sensor plugs that would go into a heat shield but they would also carry sensors through to the surface so that they could analyze things. Unfortunately I didn't get much footage from this. to imagine things. >> Okay. So, this this is our our main machine room. And then I heard you point out it's a hos machine, so Americanmade. Um it's it's so that that's that's important to us.
23:16 Um it is also well within the level of precision we need for thermal protection materials. So, >> he's your machiner guy, right? >> Yeah. Yeah. So, we we we we do not need maze or anything really impressive because everything we do, you can see it's it's held down by vacuum. Uh, this plug is held down with a a vise because it's on a mandrel, but these materials, if you try to hold them mechanically, you will damage them.
23:41 So, we have a vacuum hold down system that holds them for machining. Um, it's adjustable, so it's a low vacuum, high flow cuz they're so porous. And >> uh, as you also see, no coolants. Everything is 100% dry. And so, there's again the each the each machine has a stove pipe that goes up and out to a large industrial dust collector. You can see the snorkel right here.
24:02 It's moved away right now so you can see the drilling happening. But normally that snorkel is aimed right at the cutter and so the cutter will throw the dust off and it goes right in the dust collection. So it's all completely dry, no oils. And so this is a this is a plug mockup. So whenever we do instrumentation like we did for Artemis, we machine a a blank plug down here.
24:27 That plug goes upstairs. It gets thermalouple wires and um different insulator materials put on it to insulate the wires and then it leaves here and and goes for insulation on Artemis. >> So when you're machining this, you got to figure out just how fast you could machine it to stop it getting too hot cuz it is TPS. You don't want it to change properties, right?
24:47 >> That's true. But they don't actually generate very much heat. >> Okay. >> Even dry. Uh if if we do have an issue, this this pipe right here is plumbed to a cold air nozzle. Yeah. And so we'll we'll with Where is it? Here. >> I don't know where it's mounted, but there is a cold air nozzle that that will that will blow cold air on the on the on the part.
25:05 >> And it's just air. It's not even like n and cleaner. >> Yeah, obviously. [laughter] >> And the final stop on the tour would be this lab where one of the things they would do is they would analyze materials that had gone through tests on the ground or even after test flights to space. >> This is Artemis fluent. I don't think anybody in public has seen these yet.
25:26 So, >> well, I be able to share it. >> You get to be the first group. >> Hey, how's it going? >> Hey, man. I'm Destin. >> Destin. >> So, I I will wait to talk about these until the group is up. >> I'm just going to get the close-ups, that's all. >> Certainly. >> And so, I'm pretty sure I recognize what these were right away. And it looks like they'd actually flown.
25:43 And they are the compression pads which are used to support the weight of the capsule against the service module. Each of these can handle something like 25 tons of load. And they're donut shaped because up the middle there is the explosive bolt system which is used to hold the spacecraft on the service module. >> He'll probably tell you some stuff in a minute, >> but I'm still going to hog the cameras.
26:06 So these are uh pressure pads for Orion. Um it was a material that was invented here. It's called 3D mat and it is a really cool uh this this is something that um has been handled. So I don't know if you want to pass this around and hold it. It's kind of heavy. Um, this is a three-dimensional quartz fiber weave. So, it has fibers in X, Y, and Z directions.
26:29 Makes a really interesting structure. And then it is impregnated um or infused under pressure with a cyanite resin. And when that is cured, you get a pressure pad. And this uh had to come about because other pressure pad materials don't perform similarly enough to the the avote material uh to to to work in harmony with the the materials. So this is actually a compression pad that can handle um insane compressive loads but also function as an ablader next to the AFC coat.
27:01 So it's more in family with a coat than other pressure pad materials would have been. So this is a prototype and then I have here when it was in development we did some instrumented test articles. So this is a instrumented plug kind of like the one you saw running on the machine downstairs. And I can pass this around if you want to look at it. At the end of each of the channels down the side there's a 10,000 hole that goes all the way through it.
27:26 And we have tried to get other entities to manufacture things like this um also out of older pressure pad material types like the carbon phenolic and they come keep coming back to us uh unfinished and so far to my knowledge we're the only ones that can make a plug like these. >> So so these pads are how the spacecraft is secured to the service module.
27:43 Right. >> Yes. There are four of those and that's how it is secured for launch. And then through the center there is an explosive bolt that's that's about um probably an inch and a quarter or so diameter. And then there's an RTV um gasket around that. And so when when it separates all four of those explosive bolts are detonated and uh makes it actually a really cool clean brake.
28:06 Looks like I've seen them when it came back and it looks like they are beautifully machined the way that they >> So the bolt is pulling down onto the service module and that is reacting against that pressure. That's why it needs to be stronger than the other TPS >> that and uh during the the launch when you know all the >> handling the loads. >> Exactly.
28:25 Saddling the loads of of um Artemis 5 meter >> vibrations >> and and I don't I don't know what Artemis weighs. I should probably have that number. But um when when when you have that with the the G- Lo, right? Um these things can handle way more than that. Why do they have to have great thermal properties underneath the >> It doesn't have to have great thermal properties, but it's better if it can function sort of in family in concert with the the type of heat shield you're using.
28:52 So, if the Acoat is um recessing around a heat shield around a a compression pad that's not, you're going to get some different air flows around that compression pad that might accelerate the the ablation at that region right around it. So these flown entities or whatever these flown pieces >> these this is an actual Artemis one compression pad bolt and adhesive removed and it's been sectioned and sampled for analysis.
29:18 >> But the fact that it's going down that shows us that the bolt was recessing faster than the material around it. >> Well, this this is this is going to show you that there was there was greater heat in this region uh most likely because of the RTV gasket. Sometimes they will protrude a little bit. We call that fencing and that creates turbulent flow around that fence.
29:34 So then you also have probably additional heating here from the bolt. >> I see. Yeah. >> So that's why you see that that pattern where um out at the heat shield you have a a char layer that probably is matches pretty closely what the heat shield had. And if you look at um some of the pictures you can see online you'll see that around the com the the heat shield is not a nice clean smooth dish shape all the way across.
29:56 Um there are little ramps where each of the the compression pads are. >> So Lisa Lisa Lisa does not have a blade. we we can we can get her to reciprocate and make some noise, but she doesn't have a blade mounted. So, this is the uh benchtop article we made to prove out um the function of Bard and Lisa. This one was uh last minute because somebody thought uh well, if it if it cuts a coat, are you sure it's going to extract a sample where there's an instrumented plug?
30:22 So, we had this one made with um the aluminum oxide insulators penetrating so we could cut across and you can't even feel it when you're cutting it. It severs right through them without issue. Um, so we had a few of these made. We use them for, uh, proofing the process and for in-house testing. >> What does Lisa stand for? >> Uh, Lisa is the lesser in sizing saw for halfcoat.
30:43 [snorts] >> So the smirk on his face. >> So yeah, I I can't not do that. So So Bart is the block AFC coat removal tool. Lisa is the lesser insizing software coat. Then down here we have some of the the DFI instrumentation. This is a shock vibe test article for the spectrometer. Um how many were on Artemis 3? >> One spectrometer. >> Uh then we have heat flux.
31:10 And then we have instrumented plugs. >> So this this is a plug that's is the plug something we can pass around. >> Yes, it is. >> Okay. So this is an avote plug. This is a arcjet test article plug uh similar to what would have been on Artemis. It is um a halfcoat material. Normally this little void up here is going to be filled in with ceramic adhesive and there would be a different epoxy to to tack them in uh at the back face, but that's a arcjet test article for Artemis.
31:39 >> So I think this is something that's often overlooked that the heat shields aren't just monolithic sheets of material. Uh first for a start you have to have those bolts that go through to hold the capsule on but you also have this instrumentation that is not only detecting the state of the heat shield but in some places there are literal holes through the shield so that you can use optical sensors to look at the shock wave just outside measure the temperature measure the spectroscopy so you can see what kind of
32:06 materials are being lost from the front of the shield. So wait, is that a spectrometer that goes through the heat shield and looks at the stagnation layer or something? >> Yes, that's right. So per your point, it does have >> Let go, so it's all yours. >> Sounds good. It has an aperture open so that it can view the radiation coming from the shot. >> What do you fill that with?
32:29 >> Nothing. >> Nothing. It's just It's literally a hole. >> Uh the back half of the hole here's a cross-section is filled with uh sapphire rod. So, that's our >> optical path and then it's surrounded by an aluminina >> uh insulator and then that goes into all the mounting stuff that you see on the back. >> And all we've done here is >> created the system for the aperture and mounting that optical sapphire in the heat shield.
32:56 And then these fiber optic cables connect to the spectrometer itself which is elsewhere in the vehicle. And then I guess the the radiometer is very similar because it also point through the heat shield, right? >> Yes. >> They um they have a larger frontal area and so there is the copper and then there are a few different types of windows and coatings that we have on the radiometers.
33:19 Um so whereas the spectrometer the optical sub assembly is recessed below the outer mold line and as you see like it looks like just a little >> um when these are mounted you see a nice little copper circle with either a window or a a black emissivity coating right there flush with the surface. >> And then the recession center it just burns back and it tells you how long it is.
33:45 >> Exactly. Right. So it's just a blind hole from the inside. >> Mhm. The thought is once the surface recesses enough that that blind hole has the the surface over it removed, you can see again the light from the shock and a simple photo diode. >> Oh, it's just a photo diode looking up a hole. >> Again, that's sort of on the far end. Um I think Tommo that Tommo is it measured by a photo diode for the OS?
34:10 >> Yes, we have confirmation on that. >> But these are all basically holes through the heat shield which generally we don't talk about. >> No, >> no one wants holes in their heat shield. We poke dozens of them through. >> Well, we're doing it for science. >> So, why do we do it? Yeah, exactly. We do it for science. We do it to better understand >> Yeah.
34:27 >> the connections between the trajectory we flew, the aerothermodynamic environment that created, and then the response that that created in the material. >> And so improving that modeling helps us carry less margin with greater confidence on future missions. >> So, you don't need to fly with the holes in the heat shield anymore. >> Actually, NASA requires [laughter] that we include instrumentation on all of them.
34:48 So, we're going to continue to do the things and improve, but what it lets us do is it lets us get away with a thinner and therefore less mass. >> Oh, so a less safe heat shield. >> Bring up a fifth. >> You're hearing this, right? [laughter] >> Less safe. >> That's what the numbers tell us. >> Mass is margin. >> That's right. >> Recently, the less mass your spacecraft has, the more margin you have in launch availability.
35:08 >> And the more launch availability you have, you reduce overall risk. >> Sure. >> Actually, I have a dumb question. >> It's not my area of expertility. So, we mine either. We put holes in the heat shield, right? >> But I don't The heat doesn't conduct through that, right? Because you're not because it's going to hit it and it's going to build up pressure and it's going to flow around.
35:25 >> It's a it's a a blind hole is not in and of itself >> a a death nail is not let's work on our terminology. >> Yeah, I was [laughter] long and hard and couldn't come up with anything else. >> I don't a hole is not like he's not going to conduct through there, right? I mean it's going to be air or air is coming through and it's compressing air and it's going around have your temperature sensors your probes your sensors we need the more data the better data >> but we care deeply about sealing them and making sure that
36:00 they remain blind >> holes make >> another fabulous thing they brought out for show and tell was something that had gone through a lot of testing in the arkjet facility and when that test was over NASA proclaimed The Artemis heat shield problem had been solved. And this is the image showing two pieces of the AFC coat side by side. But the one in the bottom was the current formulation.
36:24 The one at the top was a more porous formulation which would reduce gas buildup. As I was watching one of the scientists explain this particular piece, I realized that I had in fact seen it before. >> So this is the one that we see in all the powerpoints on the heat shield. This is the actual thing. And you can tell and you and you can tell that's how that's kind of like a time time shot.
36:45 That's how it started. [clears throat] >> So the top and the bottom you see the bottom didn't look good from the very beginning. That's how it progressed. >> Had a lot of popcorn we call it. Little pieces start flying off and eventually like [clears throat] the big bigger pieces came off on the corners. Yeah. >> But this was this >> but this material has not flown yet.
37:02 So they'll be flying on Artimus 3. >> Yeah. Artemis 3 where you don't really need the extra performance cuz it's some disorbital. >> Well, no, it actually could be worse. >> Oh, okay. >> The heating is lowered. Actually, material cracks more at lower heating. That's the weird one. Yeah. So, [laughter] >> so again, it's always cool to see stuff that you've only seen in pictures in person.
37:22 So this is what happened to the material after it was placed in the arcjet facility which drives megawatt of plasma over the surface and on top of that adds a whole bunch of laser power to replicate the conditions seen during uh lunar re-entry. And so we got to the last stop in the tour which would be amazing for anyone that hadn't already gone to open source and seen these things sitting out in the open.
37:45 So for final stop, we have two panels that were extracted from Artemis 1 using BART. >> And for proof, my name's right there on the traveler. Okay, so this is one that had um a gap that ran across it and also experienced char liberation. Um, I'll have to show these in the tubs because we can't pick them up um to take them out. But so this this is the Artemis one that has the RTV gap in between uh two separate panels.
38:21 And these are the char liberation sites on this particular sample. >> Okay. >> So OKCOM thought this would be a really cool uh tour ender and then I found out half of everybody's going to be at open saw. So then kind of >> said it was the best thing I saw there. >> This is ideally what you want to see. >> Yeah. And you can see the direction the air was flowing across that by right.
38:46 >> Yes. It's really cool. I don't know if there any that are posted online, but the some of the photos that we see, you can see all of the flow paths all around the heat shield. And it's it's pretty interesting. >> My favorite photo was the one to from underneath, but it was still in the water. >> It's like piece of art. >> That's That's only Artemis.
39:03 If we if we touched on everything, I I could keep you here for the majority of a day. So, I I feel like it was a short tour, but it was probably one of the best tour, most enjoyable groups that I've taken through. So, thank you all. >> And so, that is the end of the tour. Thanks to Matt and everyone else at the lab for hosting us and answering our dumb questions.
39:21 And thanks to everyone else on the tour for asking the dumb questions so that I could pretend I was smart. And of course, thanks to NASA in general for putting on this tour. I'm Scott Manley. Fly safe.